基于锁相放大的近红外光谱信号提取电路研究  

Research on Near-Infrared Spectrum Detecting Circuit with LIA

作　　者：贾振安[1] 王培培[1] 乔学光[1,2] 周红[1] 王炜[1] 

机构地区：[1]西安石油大学光电油气测井与检测教育部重点实验室,陕西西安710065 [2]西北大学,陕西西安710069

出　　处：《仪表技术与传感器》2012年第4期104-106,共3页Instrument Technique and Sensor

基　　金：西安石油大学全日制硕士研究生创新基金项目(YS37030505);陕西省自然科学基金(2011JM8028)

摘　　要：锁相放大技术(LIA)是提取微弱信号的重要方法之一,广泛应用于近红外光谱测量领域。基于光谱吸收原理设计的甲烷检测系统,利用移相技术,实现了通过调节偏置电压的大小控制测量信号与参考信号之间的相位差,通过平衡调制解调器AD630实现了相敏滤波功能,有效地抑制了干扰,提高了系统的性能。结果表明:LIA相关器输出电压与甲烷气体体积分数呈线性关系,其线性度拟合系数为0.998 5,灵敏度为0.045 7 V/%。Lock-in amplify（LIA） is one of the important techniques for weak signal detection,so it is widely used in near-infrared spectral measurements.Based on the principle of spectrum absorption,this paper used phase shifting that by adjusting the size of the bias voltage controls the phase difference between the detected signal and reference signal,and the use of balance modemAD630 which achieves phase-sensitive detection were effective on restraining noise to improve the performance of the system.The results indicate that the output of the detective circuit is linear with the gas volume fraction,its linearity of fitting coefficients is 0.998 5,and the sensitivity is 0.045 7 V/%.

关 键 词：锁相放大器 相敏检波 移相电路 倍频电路 

分 类 号：TN721.5[电子电信—电路与系统]